vtt killed qx9650 and other 45nm cpus
:shrug:
qx9650 dead,to much vtt voltage.$1000 gone..a really GOOD read
http://www.anandtech.com/weblog/showpost.aspx?i=428
For those that are requesting proof that excessive VTT was the cause of the failure, just know that our conclusions are based more on empirical evidence than anything else; however, we have had more than one conversation with Intel CPU power engineers regarding the practical limit of VTT. In general, Intel does an excellent job of providing a wide selection of both technical and educational documents available for download by anyone directly from their website. Oftentimes significant technical insight can be gained by merely taking a few moments to read through some of these publications. As an example, anyone wishing to know more about the 45nm voltage constraints as recommend by Intel can find more information here – http://download.intel.com/design/pro...hts/318726.pdf
Intel® Core™2 Extreme Processor QX9000 Series and Intel® Core™2 Quad Processor Q9000 Series Datasheet (Document Number: 318726-003) was first published in March 2008. Section 2, Electrical Specifications, Subsection 2.6, Voltage and Current Specifications, Table 2-2, titled Absolute Minimum and Maximum Ratings, specifies absolute maximum and minimum ratings for this series of processors. It’s important to note that these values lie outside the functional limits of these processors (i.e. they may not be indicative of warranted operating voltages but are rather intended to serve as warning to those that would run their processors above rated specifications).
Table 2-2 shows maximum voltages for both VTT (FSB Termination Voltage) and VCC (Vcore) with respect to VSS (the processor power ground plane voltage, a.k.a. “ground”). In this case they happen to be equal in magnitude – 1.45V. If anything, this suggests that the use of high VTT voltages can be potentially as damaging, if not more so, than the sustained application of Vcore voltages above this same voltage yet many users continue to operate under the assumption that excessive VTT voltages should be less concerning than higher Vcore voltages.
The attitude that only Vcore can damage a CPU is one that has prevailed for far too long. Many users where initially “shocked” to learn that high PLL voltages (used to provide power to the complex array of circuits used to distribute the CPU’s common clocking signal) could permanently damage or cripple a CPU with little or no advanced warning. Even today there are those that outwardly deny the possibility of failure due to the use of VTT well in excess of Intel’s published maximum specification.
We’ve been trying for a while now to advocate a more intelligent approach to overclocking. Our loss should serve as an example for all as to the potential consequences of ignoring a little good advice. If nothing else, please don’t let our mistake become your mistake, too.
guys on evga forum with 750i and 45nm leary of vtt voltages
http://www.evga.com/forums/tm.asp?m=...1&key=񓳳
Boot up speed comparison: 680i vs 790i
http://www.evga.com/forums/tm.asp?m=320538
